FDA advisors recommend lofexidine for opioid withdrawal

SILVER SPRING, MD. – Members of the Food and Drug Administration Psychopharmacologic Drugs Advisory Committee voted 11 to 1 to recommend approval of lofexidine as the first nonopioid treatment option for the symptomatic treatment of opioid withdrawal.

Opioid withdrawal symptoms are the largest barrier to discontinuing opioid use, according to Louis Baxter, MD, executive medical director of the Professional Assistance Program in Princeton, N.J., who presented on behalf of U.S. WorldMeds, which plans to market lofexidine as Lucemyra.

Traditional withdrawal management with opioid agonists like methadone and buprenorphine can compound this issue by drawing out the detoxification process. Additionally, since these medications are opioids themselves, they present the risk for misuse, Dr. Baxter added.

Lofexidine, a selective alpha2-adrenergic receptor agonist that regulates norepinephrine release has been approved for management of opioid withdrawal in the United Kingdom since 1992.

The advisory committee voted to recommend lofexidine on the strength of the results of two randomized, double-blind, and placebo controlled phase 3 studies on the safety and efficacy of lofexidine for symptomatic treatment of opioid withdrawal between days 1 through 7. One study randomized 264 patients to lofexidine (134) or placebo (130), with patients in the treatment arm received 3.2 mg of lofexidine on days 1-5, then placebo until day 7. The second study randomized 603 patients to three groups, comparing high dose (3.2 mg/day) and low dose (2.4 mg/day) regimens of lofexidine to placebo; patients in the treatment arms took four smaller doses of lofexidine throughout the day to achieve the cumulative dose.

Researchers enrolled heavy users of short-acting opioids; heroin was the predominant agent. Both studies were conducted in the scenario of abrupt withdrawal, or the most intense withdrawal situation.

Symptomatic benefit was measured using the Short Opiate Withdrawal Scale of Gossop (SOWS-Gossop), a patient reported outcome. Patients were asked to rank their symptoms as none, mild, moderate or severe across measures like feeling sick, stomach cramps, and heart pounding among other symptoms.